The Influence Of Curing Technology And Field Maturity On Flue-cured Tobacco Aroma Constituent Contents

The composition, content, ratio and interact of tobacco aroma substance determine the aroma quality, volume and style, thus affecting the quality and industrial availability of tobacco and its products. Neutral aroma substances contribute to tobacco aroma with a large proportion. Curing process is an important step of manufacturing cigarette in which period tobacco secondary metabolize and aroma precursors mainly degrade and transform, and neutral aroma substances are also produced. So it is meaningful for improving tobacco quality to study the contents changes of neutral aroma substances and regulation factors during curing process. Presently, to improve the quality and availability of the upper leaves of tobacco is the question that we need to solve. In this research, we studied the neutral aroma substances contents in upper tobacco leaves of different maturities and curing technologies. It has directing significance for guiding collection and curing of upper leaves. The main outcomes are as follows:1. Gas chromatography was used for the contents analysis of neutral aroma substances. The condition of pretreatment was optimized and the best treatment combination was screened. A quick and effective method was created.2. Studied the change rule of the neutral aroma substances contents during the curing process. With the curing process, the degradation products of carotinoid and brown reaction increased continuely; The degradation products of percent alkanes and phenylalanine decreased after increase; The contents of neophytadiene decreased all the time. Other neutral aroma substances contents changed with no obvious rule.3. The yellowing stage of curing process had the biggest influence on tobacco neutral aroma substances contents. The temperature and humidity difference treatment was more inpactive than yellowing time treatment. The content of neutral aroma substance was relatively higer in 2.0℃of temperature and humidity difference and 54h treatment.4. The accumulation of aroma substance also varied obviously in leaves of different position. The content of neutral aroma substance was higer in top 1-3 leaves than in top 4～6 leaves with the same curing condition.5. Maturity had a great influence on upper leaves neutral aroma substances composition and contents. The contents of brown reaction products were higer in ripe leaves than in full ripe leaves; The contents of degradation products of carotenoids and percent alkanes and phenylalanineis increasad with tobacco leaf maturity improved; The total amount of neutral aroma substances was maximum also in full ripe leaves, then in the ripe leaves and the last was in undercure leaves.6. According to the division of aroma substances groups, the contents of aldehyde substances were almost the same in three degrees of maturity, and the contents of ketones and alcohols increasad with tobacco leaf maturity improved.